Re: [PATCH] MIPS: Loongson64: Add read_persistent_clock64()

[Tiezhu Yang]

On 11/12/2020 06:09 PM, Jiaxun Yang wrote:
> 在 2020/11/12 18:04, Jiaxun Yang 写道:
> > Hi Tiezhu,
> >
> > 在 2020/11/12 16:29, Tiezhu Yang 写道:
> > > Add read_persistent_clock64() to read the time from the battery backed
> > > persistent clock. With this patch, we can fix the wrong time issue due
> > > to the system clock is not consistent with hardware clock after resume
> > > from sleep state S3 (suspend to RAM), at the same time, the system time
> > > can be right instead of "Thu Jan 1 08:00:00 CST 1970" without rtc 
> > > driver.
> > >
> > > start_kernel()
> > >    timekeeping_init()
> > >      read_persistent_wall_and_boot_offset()
> > >        read_persistent_clock64()
> > >
> > > timekeeping_resume()
> > >    read_persistent_clock64()
> > >
> > > timekeeping_suspend()
> > >    read_persistent_clock64()
> >
> > It is highly discoraged to do anything with bridgetype, which isn't 
> > probed via
> > devicetree.
> >
> > Please check if you can deal with that inside RTC framework, or make 
> > it as
> > a part of RTC driver (e.g. set up a callback).
> >
> > Also you should submit RTC driver at first if you intend to complete 
> > LS7A support.
>
> Oops,
> Just dig it deeper, I guess simply select RTC_HCTOSYS would solve the 
> issue.
> We're trying very hard to decouple all the drivers and conponents,
> DeviceTree for all!

+cc WANG Xuerui <git@xxxxxxxxxx>

Hi Jiaxun,

Thanks for your reply.

Xuerui has already submitted the patch of LS7A rtc driver [1],
but not yet been merged into the mainline kernel, I discussed
with him early today.

Do you mean that read_persistent_clock64() can call the function
like rtc_read_time() defined in rtc driver?

Thanks,
Tiezhu

[1] 
https://patchwork.kernel.org/project/linux-mips/patch/20200923075845.360974-2-git@xxxxxxxxxx/

> > Thanks.
> >
> > - Jiaxun
> >
> > > Signed-off-by: Yinglu Yang <yangyinglu@xxxxxxxxxxx>
> > > Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> > > ---